The Official Way to Jump-Start a Battery

Everyone thinks they know how to jump-start a car, whether it’s what grandpa taught or what they heard from a friend of a friend.

It’s time to set the record straight.

How to Jump-start a Car

Step Zero: The Four-Step Pre-Check

A battery may fail for a number of reasons, some of which could present a hazard to anyone who tries to jump-start the battery. Here are four quick checks professional technicians and car lovers alike should do before trying to jump-start a battery.

Check your safety. Work in a well-ventilated area away from smoke, sparks or flames. Remove jewelry or accessories, including watches, rings and necklaces. Put on appropriate hand and eye protection. Never lean over a battery when jump-starting it.

Check for a smell. If you detect a scent similar to rotten eggs, that means the battery may be leaking dangerous gas. Do not to jump-start the vehicle. Seek alternate transportation and let a professional step in.

Check for heat. Heat radiating from the battery’s case means it has been attempting to recharge or discharge faster than it should. Leave the hood up and wait for the battery to cool before taking any action.

Check for corrosion. Corrosion can hinder any kind of electrical connection, whether it’s jumper cables or the vehicle’s own terminals. Clear off excessive corrosion with a brush, battery cleaner or a water-and-baking soda mixture.

Step 1. Shut everything down.

The car and any vehicle accessories must be off, so that all the power goes to starting the engine and not to charging a phone.

Step 2. Start with the positive cables.

Attach the positive (usually the red) cable to the positive terminal on the dead battery.

Then connect the positive to the good battery. As you move the jumper cables around, take extra precautions to keep the clamps from touching.

Step 3. Next goes the negative.

Now, connect the negative (usually the black) clamp to the good battery's post.

Then, take the second negative connection to the frame of the dead vehicle or to the engine block itself. Connect it as far from the battery as you can -- which usually isn't much. That's why we recommend the frame of the car.

Step 4. Start your engines, good battery first.

Start the good battery’s engine, and then start the other.

While you've got them connected, rev the good battery's engine to about 1,500 RPMs. This will build up a little more charge in the dead battery, but it still needs replacing. Now, you can actually drive it to a repair shop or a dealership.

Step 5. Remove the cables in opposite order.

Start negative first, then positive. First goes the negative clamp you connected to the dead vehicle's frame, then the black clamp on the good battery. Then the good battery's positive clamp -- and lastly the positive clamp on the dead battery.

This is a lot of cable handling, so stay extra careful. Don't let the clamps touch each other as you move between battery connections.

Experts Agree: Jump-starting Is a Pain

Jump-starting a battery is a risky, hazardous, meticulous process for a temporary solution. Anyone following these instructions assumes the risk for their own safety, and should follow all reasonable precautions they can.

Interstate's experts all recommend you skip the jump-starting headache.